Etude numérique du transfert de chaleur en 2D et 3D dans une centrale à cheminée solaire et amélioration des performances.

Abstract

The solar chimney is a generator of electrical power from solar energy, based on the conversion of the kinetic energy generated by natural convection into mechanical energy. However, the efficiency of this recent technique remains low compared to other processes. In order to increase the productivity of this system, our study has examined two essential techniques that have a direct impact on the performance, the first concerns the improvement of heat transfer which is an important factor to optimize the design of the chimney solar energy and the second is related to the combination of solar energy with other systems. In order to show the effect of heat transfer, two geometrical configurations of the solar chimney were considered. A two-dimensional, dimensionless numerical study with Fluent software, as a function of Rayleigh number and for both laminar and turbulent flow regimes, was undertaken. The possibility of combining a solar chimney with a gas turbine was studied. The injection of the exhaust gas at the inlet or in the middle of the collector was examined. In addition, a three-dimensional study was conducted to show the influence of the third direction on the flow and heat transfer in both laminar and turbulent regimes. The results obtained show that the position of the wind turbine in the geometrical configuration studied has an effect on the two velocity profiles at the outlet of the collector and at the inlet of the chimney. Moreover, it is clear that the coupling of the solar chimney with a gas turbine contributes to significantly improving the efficiency. The effect of the third direction was found in purely convective regimes.